METHOD CONTROLLING COMPOSITION OF GAS MIXTURES AND LIQUID MEDIA Russian patent published in 1998 - IPC

FIELD: systems controlling technological processes at industrial plants. SUBSTANCE: tested medium with composition known at moment of first test measurement is passed periodically or continuously through waveguide with known parameters, short-time acoustic sinusoidal oscillations are excited in it, then they are converted to electric signals that are amplified, measured and converted to code- oscillation period, measured and converted to code-medium temperature in waveguide. After this velocity of sound, rate of change of acoustic pressure for moment of transition of voltage of electric signal through zero value are calculated. Then short-time sinusoidal oscillations are excited periodically, time intervals between excitation moments, signal amplitude, oscillation period, medium temperature are measured. Velocity of sound, rate of change of acoustic pressure are calculated. Starting from second measurement one judges change of composition of medium by calculation of rate of change of volume fractions of components of medium. On growing section of change of signal there are isolated two threshold values of voltage with the aid of two- threshold device, duration of interval corresponding to these threshold values and rate of change of acoustic pressure within this interval is calculated by proper expression. EFFECT: expanded functional capabilities, simplification of device and enhanced accuracy of test. 2 cl, 2 dwg